/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2011-09-23     Bernard      the first version
 * 2011-10-05     Bernard      add thumb mode
 */
#include <armv7.h>
#include <board.h>
#include <rtthread.h>

/**
 * @addtogroup AM33xx
 */
/*@{*/

/**
 * This function will initialize thread stack
 *
 * @param tentry the entry of thread
 * @param parameter the parameter of entry
 * @param stack_addr the beginning stack address
 * @param texit the function will be called when thread exit
 *
 * @return stack address
 */
rt_uint8_t* rt_hw_stack_init(void* tentry, void* parameter,
                             rt_uint8_t* stack_addr, void* texit) {
    rt_uint32_t* stk;

    stack_addr += sizeof(rt_uint32_t);
    stack_addr = (rt_uint8_t*)RT_ALIGN_DOWN((rt_uint32_t)stack_addr, 8);
    stk = (rt_uint32_t*)stack_addr;
    *(--stk) = (rt_uint32_t)tentry;    /* entry point */
    *(--stk) = (rt_uint32_t)texit;     /* lr */
    *(--stk) = 0xdeadbeef;             /* r12 */
    *(--stk) = 0xdeadbeef;             /* r11 */
    *(--stk) = 0xdeadbeef;             /* r10 */
    *(--stk) = 0xdeadbeef;             /* r9 */
    *(--stk) = 0xdeadbeef;             /* r8 */
    *(--stk) = 0xdeadbeef;             /* r7 */
    *(--stk) = 0xdeadbeef;             /* r6 */
    *(--stk) = 0xdeadbeef;             /* r5 */
    *(--stk) = 0xdeadbeef;             /* r4 */
    *(--stk) = 0xdeadbeef;             /* r3 */
    *(--stk) = 0xdeadbeef;             /* r2 */
    *(--stk) = 0xdeadbeef;             /* r1 */
    *(--stk) = (rt_uint32_t)parameter; /* r0 : argument */
    /* cpsr */
    if ((rt_uint32_t)tentry & 0x01)
        *(--stk) = SVCMODE | 0x20; /* thumb mode */
    else
        *(--stk) = SVCMODE; /* arm mode   */

#ifdef RT_USING_LWP
    *(--stk) = 0; /* user lr */
    *(--stk) = 0; /* user sp*/
#endif
#ifdef RT_USING_FPU
    *(--stk) = 0; /* not use fpu*/
#endif

    /* return task's current stack address */
    return (rt_uint8_t*)stk;
}

/*@}*/
